1. Field of Invention
The present invention relates to a liquid crystal display, an image data compensation circuit, an image data compensation method, and an electronic apparatus, in which flickering or the like is appropriately reduced, minimized or prevented over the entire display region.
2. Description of Related Art
A conventional liquid crystal display, such as an active matrix liquid crystal display, is primarily formed of a liquid crystal panel, a processing circuit, and a timing control circuit. Among these components, the liquid crystal panel is formed of a pair of substrates with TN (Twisted Nematic) liquid crystals provided therebetween. Specifically, out of the pair of substrates, one substrate is provided with a plurality of scanning lines and a plurality of data lines. The scanning lines and the data lines intersect each other and are electrically insulated from each other. At each of these intersections, a pair of a thin film transistor (hereinafter referred to as a “TFT”), which is an example of a switching element, and a pixel electrode is provided.
The other substrate is provided with a transparent counter electrode (common electrode) opposed to the pixel electrodes, and the counter electrode is maintained at a predetermined potential. Opposing surfaces of the two substrates are provided with alignment layers, which are rubbed so that liquid crystal molecules are continuously twisted approximately 90 degrees in the major axis direction between the two substrates. Back surfaces of the two substrates are provided with polarizers in accordance with the alignment direction.
Concerning the TFTs which are provided at the intersections of the scanning lines and the data lines, when a scanning signal (gate signal) applied to the corresponding scanning line becomes the ON-state potential, a connection between the source connected to the data line and the drain connected to the pixel electrode is established. Thus, an image signal supplied to the data line is applied to the pixel electrode, and the potential difference between the potential of the counter electrode and the potential of the image signal is applied to a liquid crystal capacitor formed of the pixel electrode, the counter electrode, and the liquid crystal therebetween. If the switching is turned OFF, the liquid crystal capacitor maintains the applied potential difference in accordance with the characteristics of the liquid crystal capacitor and a storage capacitor.
If the effective value of a voltage (hereinafter referred to as the “effective voltage”) applied to the liquid crystal capacitor is zero, light which passes through the liquid crystal capacitor is rotated by approximately 90 degrees along the twisting of the liquid crystal molecules. As the effective voltage increases, the liquid crystal molecules tilt toward the electrical field direction. As a result, the optical activity is lost. For example, in a transmissive liquid crystal display, when polarizers in which polarizing axes are orthogonal to each other in accordance with the alignment direction are formed at the light-incident side and the back side (in normally white mode), and when the effective voltage applied to the liquid crystal capacitor is zero, the transmissivity is maximized (thereby displaying white). As the effective voltage applied across the two electrodes increases, light is blocked, and eventually the transmissivity is minimized (thus displaying black).
By driving the scanning lines and the data lines with appropriate timing, the effective voltage in accordance with the gray level can be applied to each liquid crystal capacitor. As a result, gray-scale display in which the gray-level differs for each pixel can be performed.
In principle, a liquid crystal display employs an alternating current (AC) driving method for driving the liquid crystal capacitor in order to prevent deterioration of the liquid crystal, which is caused by application of a direct current (DC) component. An image signal applied to the pixel electrode via the data line is alternately inverted every predetermined period between the positive polarity and the negative polarity on the basis of a predetermined constant potential Vc.